Re: Updated git HOWTO for kernel hackers

[Amin Azez <azez@ufomechanic.net>]

Dave Jones daily snapshot of git solved the problem, available from:
http://www.codemonkey.org.uk/projects/git-snapshots/git/

I realise that Jeff's howto suggested updating git using git, but it
suggested doing this after following the intermediate steps. I also find
it ironic that the version of git Jeff provides doesn't work with his
instructions; however, still many thanks to Jeff for his HOWTO and to
Dave for git.

Azez

Amin Azez wrote:
> Thanks for the HOWTO, Jeff, but it gives me problems in step 4.
> I checked out your latest git source today and "make install"ed it as
> part of your instructions and at step 4 I get:
> 
> $ git checkout -f
> error: cannot map sha1 file f8640c306db2d583b9a30f2e52f8fb0a4cf624e0
> fatal: failed to unpack tree object
> a92b7b80579fe68fe229892815c750f6652eb6a9
> 
> $ cat .git/HEAD
> a92b7b80579fe68fe229892815c750f6652eb6a9
> 
> Naturally I have no idea what f8640c306db2d583b9a30f2e52f8fb0a4cf624e0
> refers to.
> 
> Step 3:
> $ git-pull-script \
> rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
> 
> said I was already up to date.
> 
> Variations on step 4:
> 
> $ git-read-tree -m HEAD
> or
> $ git-read-tree a92b7b80579fe68fe229892815c750f6652eb6a9
> also fail in the same way.
> 
> My linux-2.6 directory only has one entry, .git, containing about 75M of
> files.
> 
> Sam
> 
> Jeff Garzik wrote:
> 
>>
>> Things in git-land are moving at lightning speed, and usability has
>> improved a lot since my post a month ago: 
>> http://lkml.org/lkml/2005/5/26/11
>>
>>
>>
>> 1) installing git
>>
>> git requires bootstrapping, since you must have git installed in order
>> to check out git.git (git repo), and linux-2.6.git (kernel repo).  I
>> have put together a bootstrap tarball of today's git repository.
>>
>> Download tarball from:
>> http://www.kernel.org/pub/linux/kernel/people/jgarzik/git-20050622.tar.bz2
>>
>>
>> tarball build-deps:  zlib, libcurl, libcrypto (openssl)
>>
>> install tarball:  unpack && make && sudo make prefix=/usr/local install
>>
>> jgarzik helper scripts, not in official git distribution:
>> http://www.kernel.org/pub/linux/kernel/people/jgarzik/git-new-branch
>> http://www.kernel.org/pub/linux/kernel/people/jgarzik/git-changes-script
>>
>> After reading the rest of this document, come back and update your
>> copy of git to the latest:
>> rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/git.git
>>
>>
>> 2) download a linux kernel tree for the very first time
>>
>> $ mkdir -p linux-2.6/.git
>> $ cd linux-2.6
>> $ rsync -a --delete --verbose --stats --progress \
>> rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git/
>> \          <- word-wrapped backslash; sigh
>>     .git/
>>
>>
>> 3) update local kernel tree to latest 2.6.x upstream ("fast-forward
>> merge")
>>
>> $ cd linux-2.6
>> $ git-pull-script \
>> rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
>>
>>
>> 4) check out files from the git repository into the working directory
>>
>> $ git checkout -f
>>
>>
>> 5) check in your own modifications (e.g. do some hacking, or apply a
>> patch)
>>
>> # go to repo
>> $ cd linux-2.6
>>
>> # make some modifications
>> $ patch -sp1 < /tmp/my.patch
>> $ diffstat -p1 < /tmp/my.patch
>>
>> # NOTE: add '--add' and/or '--remove' if files were added or removed
>> $ git-update-cache <list of all files changed>
>>
>> # check in changes
>> $ git commit
>>
>>
>> 6) List all changes in working dir, in diff format.
>>
>> $ git-diff-cache -p HEAD
>>
>>
>> 7) List all changesets (i.e. show each cset's description text) in
>> local branch of local tree, that are not present in remote tree.
>>
>> $ cd my-kernel-tree-2.6
>> $ git-changes-script -L ../linux-2.6 | less
>>
>>
>> 8) List all changesets:
>>
>> $ git-whatchanged
>>
>>
>> 9) apply all patches in a Berkeley mbox-format file
>>
>> First, download and add to your PATH Linus's git tools:
>> rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/git-tools.git
>>
>> $ cd my-kernel-tree-2.6
>> $ dotest /path/to/mbox  # yes, Linus has no taste in naming scripts
>>
>>
>> 10) don't forget to download tags from time to time.
>>
>> git-pull-script only downloads sha1-indexed object data, and the
>> requested remote head.  This misses updates to the .git/refs/tags/ and
>> .git/refs/heads directories.  It is advisable to update your kernel
>> .git directories periodically with a full rsync command, to make sure
>> you got everything:
>>
>> $ cd linux-2.6
>> $ rsync -a --delete --verbose --stats --progress \
>> rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git/
>> \          <- word-wrapped backslash; sigh
>>     .git/
>>
>>
>> 11) list all branches, such as those found in my netdev-2.6 or
>> libata-dev trees.
>>
>> Download
>> rsync://rsync.kernel.org/pub/scm/linux/kernel/git/jgarzik/netdev-2.6.git
>>     or
>> rsync://rsync.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev.git
>>
>>
>> $ cd netdev-2.6
>> $ ls .git/refs/heads/
>>
>> { these are the current netdev-2.6 branches }
>>
>>> 8139cp       forcedeth    master     qeth           smc91x         we18
>>> 8139too-iomap  for-linus    natsemi      r8169      smc91x-eeprom  wifi
>>> airo           hdlc         ns83820      register-netdev  starfire
>>> atmel          ieee80211    orinoco      remove-drivers   tlan
>>> chelsio        iff-running  orinoco-hch  sis900           veth
>>> dm9000         janitor      ppp          skge             viro
>>
>>
>>
>>
>> 12) make desired branch current in working directory
>>
>> $ git checkout -f $branch
>>
>>
>> 13) create a new branch, and make it current
>>
>> $ cp .git/refs/heads/master .git/refs/heads/my-new-branch-name
>> $ git checkout -f my-new-branch-name
>>
>>
>> 14) examine which branch is current
>>
>> $ ls -l .git/HEAD
>>
>>
>> 15) undo all local modifications (same as checkout):
>>
>> $ git checkout -f
>>
>>
>> 16) obtain a diff between current branch, and master branch
>>
>> In most trees WITH BRANCHES, .git/refs/heads/master contains the
>> current 'vanilla' upstream tree, for easy diffing and merging.  (in
>> trees without branches, 'master' simply contains your latest changes)
>>
>> $ git-diff-tree -p master HEAD
>>
>>
>> -
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